Thermal isolation of oven liner



Nov. 27, 1962 B. HURKO 3,066,212

THERMAL ISOLATION OF OVEN LINER Filed July 21, 1960 FIG! 14 FCIZ INVENTOR. BOHDAN HURKO B 2 i {K a HIS ATTORNEY United States Patent Qffice 3,056,212 Patented Nov. 2?, 1962 3,066,212 THERE 1A1 ISOLATION OF OVEN LINER Bohdan Hnriro, Louisville, Ky., assignor to General Electri-c @ornpany, a corporation of New York Filed July 21, 196i), Ser. No. 44,369 7 tllaims. (Cl. 21935) The present invention relates to a design for mounting an oven liner in the body of a domestic range so as to reduce the heat flow from the liner to the body thereby limiting the heat loss from the oven cavity.

This invention is an outgrowth of a recent discovery in the range art that the walls of the oven liner may be cleaned automatically of food particles and grease spatterings by raising the temperature of the oven cavity to around 800950 F. This extreme temperature burns off the food soil and results in a spotless oven interior as is described in my copending application entitled Automatic Gven. Cleaning, Serial No. 27,926, filed May 9, 1960, and assigned to the same assignee as is the present invention. The normal baking temperatures extend up to a maximum of about 550 F. so that a heat cleaning operation is increasing the maximum baking oven temperature by about 400 F. It is important to prevent the temperature from dropping appreciably in the vicinity of the door opening due to heat flow through and around the door, and from the oven liner to the range body by way of the mounting means. If heat is allowed to escape from the oven liner to any appreciable extent the oven temperature may drop several hundred degrees and it will be impossible to burn off the food soil in this cool zone.

The principal object of the present invention is to provide an oven for a range with only limited metal contacting surfaces between the front of the oven liner and the range body to thermally insulate the liner therefrom.

A further object of the present invention is to provide an oven for a range with only limited metal contact between the front of the oven liner and the range body while at the same time permitting the utilization of standard pull-back clamps for supporting the oven liner in place.

A still further object of the present invention is to provide an oven for a range wherein a non-metallic breaker frame is disposed between the front of the oven liner and the range body for sealing cooperation with the oven door.

A preferred embodiment of the present invention comprises an oven liner that has a front opening normally closed by a door. In the illustrated embodiment the oven cavity is heated by electrical heating means. It is to be understood, however, that this invention is also applicable to ovens provided with gas burners. As is customary, the metallic oven liner is enclosed in an outer metallic range body from which it is thermally insulated by a blanket of suitable heat insulating material. There is an opening in the front of the range body so that the oven liner may be inserted therethrough. This front opening is provided with a series of inwardly-extending brackets that are widely spaced around the opening. The brackets along the bottom of the opening serve to support the weight of the oven liner. The front portion of the liner is provid-ed with flange means for engaging the aforementioned brackets so that the oven liner may be supported in the range body by applying a tension force with pull-back clamps at the back of the oven tending to pull the liner into the range body and against the brackets. Moreover, a thermal insulating, non-metallic breaker frame is attached to the front opening of the range body for sealing against the front of the oven liner and the inner surface of the oven door while also substantially isolating the liner from the range body.

My invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

FIGURE 1 is a left side elevational view partly in cross-section of a free-standing range embodying the present invention;

FIGURE 2 is a top plan fragmentary cross-sectional view showing the supporting and sealing arrangement adjacent one side of the door and is taken on the line 22 of FIGURE 1; and

FIGURE 3 is a detail showing of one of the inwardlyextending brackets.

Turning now to consideration of the drawing and in particular to FIGURE 1, there is shown a free-standing electric range having a top cooking surface 11 with a plurality of surface heating elements 12, an oven cavity 13, a front opening oven door 14 and a backsplasher 15 located along the back edge of the cooktop 11 for controlling the energization of the various heating elements of the range. The oven cavity 13 is formed by a metallic oven liner 16 and a front door 14 having an inner door liner 50. The door is hinged at its bottom'to the range body as is shown at 27 in FIGURE 1. The oven liner is a box-like construction and it has a bottom wall 17, two parallel side walls 18, a top wall 19 and a back wall 20. The front wall of the oven liner is open as at 21 and this opening is adapted to be closed by the inner door liner 5%, of the door 14. As in standard electric ovens there is a lower heating element or bake unit 22 and an upper heating element or broil unit 23. Both the bake and broil units 22 and 23 are plug-in units that are inserted into connectors 24 positioned in openings in the back wall of the oven liner as is well understood in this art. The oven liner 16 is insulated with a relatively thick blanket of insulation 25 formed of a suitable thermal insulating material, such as fiberglass, and is supported within the outer metallic range body 26 by the invention to be explained hereinafter.

The front of the range body 26 has an opening defined by an inwardly-directed flange 36 that extends around the opening and is of such overall size that it permits the oven liner 16 to be assembled therethrough. Fastened to the outer side of this flange 3t) are a series of L-shaped supporting brackets 31 which extend inwardly from the opening and are widely spaced from each other. The shank of the L-bracket 31 is attached to the flange 36 while the foot of the L is formed at right angles thereto and extends toward the opposite wall of the oven liner. In actual practice, two such brackets are located along the bottom edge of the front opening, while there is one bracket along each side wall and one at the top of the oven liner. These widely spaced brackets provide supporting, bracing and bearing surfaces against which the oven liner may be pulled from the back of the range body. A like series of angle flanges 32 are attached to the outer front portion of the oven liner for cooperative engagement with the L-shaped brackets 31. The tips of the brackets 31 which engage the angle flanges are pointed as at 31a in FIGURE 3 to reduce the area of contact with the flange 32 and restrict the heat flow therebetween.

The back wall 29 of the oven liner includes a pair of adjustable clamping members 33 (only one of which is shown), each comprising a strap member 34 fastened to the outer surface of the back wall 20 and a J-bolt 36. Each strap has an opening 35 for receiving the hook of the J-bolt member. This bolt extends through an opening in a back panel 37 of the range body and a fastening nut 38 is threaded onto the end of the bolt and tightened to draw the oven liner into the range body and the angle flanges 32 into engagement with the L-shaped brackets 31. In order to reduce the heat flow from the oven liner through the angle flanges 32 and into the L- shaped brackets 31, fastening screws 40 are assembled to the back of the angle flanges so that the rounded heads of the screws have nearly point contact with the brackets 31. Of course, this is only one example of many ways of providing reduced area contact between the flanges 32 and brackets 31. Another possibility would be to use embossments or lancings on the brackets or flanges to provide limited areas of contact.

Wrapped around the outer periphery of the front portion of the oven liner is an electric mullion heater element 42 of the tubular sheath type for replenishing the heat lost from the oven cavity through and around the door 14. An aluminum reflector 43 overlies the mullion heater 42 for redirecting the radiant energy of the heating element back toward the oven liner. This reflector is supported from the angle flanges 32 by the same fastening screws 4t? as previously described. Attention is directed to the annular lip 45 formed on the front edge of the oven liner and extending outwardly therefrom to form a pocket in which the mullion heater is positioned.

The above discussion explained the means for supporting the oven liner, but no means were provided for closing the opening between the front of the oven liner and the range body. This need is met by a non-metallic breaker frame in the form of a thermal insulating gasket '37 of fiberglass or the like material of woven tubular construction. A breaker frame may be defined for purposes of this discussion as a member that frames the oven opening in the front of the range body and forms a break or a discontinuous surface bridging the gap between the front of the oven liner and the front of the range body. One edge of the gasket is flattened out by the metal frame i8 which is assembled by screw fasteners 49 to the inner flange 34) of the front opening of the range body. The innermost edge of the gasket, being unconfined, expands outwardly to form a sealing and shielding member that is braced against the annular lip 45 of the over liner and is adapted to contact both the side of the inner door liner 5e and the inner side 51 of the door to provide a double sealing action with the door. While only one sealing means is provided for the door, it should be understood that additional gaskets could be added, such as a silicone rubber gasket mounted on the inner side of the door, without departing from the scope of this invention.

Having described above my invention of a novel mounting means and a non-metallic breaker frame for the oven liner of the heat cleaning oven it will be readily apparent to those skilled in this art that I have isolated the oven liner from the range body so that only a very small temperature drop will occur in the oven liner adiacent the door. Moreover, I have devised a design which is strong and durable and will withstand the severe shocks to which large appliances are exposed during the humping and transit of rail cars. In addition the thermal isolation is so complete that it is possible to utilize but a single combined gasket and breaker frame for sealing the oven door rather than using the double gasketing arrangement as previously taught.

Other modifications of this invention will occur to those skilled in this art and it is to be understood, therefore, that this invention is not limited to the particular embodiments disclosed but that it is intended to cover all modifications which are within the true spirit and scope of this invention as claimed. 7

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An oven comprising an oven liner of box-like construction with a bottom wall, a pair of side walls, a top wall, a back wall, and a front opening for gaining access thereto, a range body surrounding the oven liner and including thermal insulation to insulate the liner from the body, an oven door hinged to the front of the range body for closing the front opening of the oven liner, the rage body also having a front opening for receiving the oven liner therethrough, a series of widely spaced brackets fixed to the range body and extending inwardly of the front opening thereof, and adiustable fastening means connected between the back of the oven liner and the range body, the front portion of the oven liner having an outer flange means so that the oven liner may be pulled into the ran e body by means of the fastening means until the flange means pulls against the brackets with only limited metal contact between the two members, the range body including a thermal insulating non-metallic breaker frame fastened within the front opening thereof for shielding the front portion of the oven liner from the oven door when the door is closed.

2. An oven as recited in claim 1 wherein an electric heating element is wound around the outer periphery of the front portion of the oven liner, and where the said flange means supports a thermal reflector for directing the heat energy of the heater toward the oven liner, and fastening means extending through said flange means for supporting the reflector on the flange means and also providing the limited metal contact between the flange means and the brackets of the range body.

3. An oven as recited in claim 1 wherein the said thermal insulating non-metallic breaker frame is a woven material of tubular form that is fastened to the innerside of the opening of the range body and bears against the front portion of the oven liner to form a breaker frame insulating the oven liner from the range body and having double contacting surfaces with the inner surface of the door.

4. An electric oven supported in a range body where the oven comprises an oven liner of box-like construction having a bottom wall, a pair of side walls, a top wall, a back wall and a front opening for gaining access thereto, the range body also having a front opening for receiving the oven liner therethrough, and thermal insulation installed in the range body and surrounding the oven liner to insulate the liner from the body, the front edge of the oven liner having an outwardly directed lip, and electric mullion heater element located just behind this lip and extending around the periphery of the oven liner for adding heat to the oven liner in this area, a thermal reflector overlying the mullion heater for directing the radiant energy toward the oven liner to prevent the loss of heat through the range body, a series of widely spaced brackets extending around the front opening in the range body and directed inwardly thereof, the oven liner being supported on the brackets along the bottom of the front opening, and adjustable clamping means at the back of the range body for pulling against the oven liner until the front portion of the oven liner is braced against the said brackets, and a combined insulating gasket and breaker frame fastened to the front opening of the range body and braced against the front of the oven liner for shielding the oven liner from the range body, there being low heat conductivity between the oven liner and the brackets to restrict the heat flow from the liner to the range body.

5. An oven comprising an oven liner of box-like construction with a bottom wall, a pair of side walls, a top wall, a back wall, and a front opening for gaining access thereto, and an oven door hingedly supported at the front of the oven for closing the front opening of the oven liner, a range body surrounding the oven liner and including thermal insulation to insulate the liner from the body, the liner being supported in the range body by means located remotely from the front edge of the liner, and having limited areas of metal heat conducting surfaces between the liner and range body, and a combined thermal insulating non-metallic breaker frame and sealing gasket positioned between the front edge of the liner and the front wall of the range body for shielding the heat flow path from the oven liner to the range body, and sealing between these members as well as with the oven door.

6. An oven as recited in claim 5 wherein the combined breaker frame and gasket is formed of a woven fiberglass material of tubular construction that is mounted within the front opening in the range body.

7. An oven as recited in claim 5 wherein the range body has an opening in its front Wall, and a series of Widely spaced brackets supported behind the opening, the oven liner having widely spaced flange means fixed to the outer surface and back from the front portion of the liner, and adjustable clamping members at the back of the Oven so that the oven liner may be fastened in the range body with the flange means braced against the said brackets so there are limited areas of heat conducting surfaces between the liner and the range body near the front edge of the liner.

References Cited in the file of this patent UNITED STATES PATENTS 1,477,454 Seibert Dec. 11, 1923 2,263,831 Welch Nov. 25, 1941 2,408,295 Cossin Sept. 24, 1946 2,646,762 Ingraham et al July 28, 1953 2,858,408 Barroero Oct. 28, 1958 2,912,727 Sehn Nov. 17, 1959 

